Irresistable Grace

One of the basic tenant of Calvinism is irresistible Grace, the idea man cannot resist or refuse the grace God has given if a Christian. II Corinthians seems to disprove the entire concept. Paul said in II Corinthians 1 that he walked by the grace of God. Yet, he doesn't say grace is irresistible and makes it known he is still a sinner.

Paul refutes the idea of irresistible grace in multiple verses.

2Co 6:1  We then,G1161 as workers togetherG4903 with him, beseechG3870 you alsoG2532 that yeG5209 receiveG1209 notG3361 theG3588 graceG5485 of GodG2316 inG1519 vain.G2756 

It seems obvious they receive grace in a way that it did them no good. Grace was likely made known to them but they did not receive it in a way that salvation would follow. Grace does not force belief or obedience.